Method for adjusting the useful signal in binaural hearing aid systems and hearing aid system

Abstract

A method operates a hearing aid system and the hearing aid system has at least two hearing aid devices, between which a signal path is provided, and with at least one signal processing unit, which is provided to process audio signals. In the method the signal processing apparatus filters first audio signals with a filter predetermined for a defined spatial direction, from which a useful signal arrives, so that second audio signals are generated, in which the components of the useful signal in the second audio signals are equalized to a greater degree than in the first audio signals. The second audio signals are then filtered with an adaptive filter, so that third audio signals are generated, in which the components of the useful signal are equalized to an even greater degree than in the second audio signals.

The invention claimed is: 
     
       1. A method for operating a hearing aid system with at least two hearing aid devices, one of the hearing aid devices provided for each ear of a user, the hearing aid devices each having a transducer for receiving an acoustic signal and converting the acoustic signal in each instance to a first audio signal, each of the hearing aid devices having a signal processing unit and a bidirectional exchange of the first audio signals taking place between the signal processing units of the hearing aid devices, the hearing aid system having a signal processing apparatus for processing audio signals and the hearing aid system having a signal connection for transmitting the first audio signal from each hearing aid device to the signal processing apparatus, wherein the signal processing apparatus executing the following steps for equalizing components of a useful signal in received audio signals of the acoustic signal in third audio signals, the useful signal arriving from a defined spatial direction in relation to the hearing aid system:
 filtering first audio signals with a predetermined filter predetermined for the defined spatial direction, so that second audio signals are generated, the predetermined filter being configured in such a manner that the components of the useful signal in the second audio signals are equalized to a greater degree than in the first audio signals; and 
 filtering the second audio signals with an adaptive filter, so that the third audio signals are generated, the adaptive filter being configured in such a manner that the components of the useful signal in the third audio signals are equalized to a greater degree than in the second audio signals. 
 
     
     
       2. The method according to  claim 1 , wherein the signal processing apparatus having means for dividing the first audio signals into predefined frequency ranges and the steps of  claim 1  being executed separately for each audio signal in a frequency range. 
     
     
       3. The method according to  claim 1 , wherein the predetermined filter is defined by a predetermined number of predetermined coefficients. 
     
     
       4. The method according to  claim 3 , wherein the predetermined number of predetermined coefficients differing in different frequency ranges. 
     
     
       5. The method according to  claim 3 , wherein the predetermined coefficients for the predetermined filter being predetermined for at least two predetermined spatial directions. 
     
     
       6. The method according to  claim 5 , which further comprises performing the following steps in the step of filtering the first audio signals:
 estimating an estimated spatial direction of the useful signal; and 
 assigning the predetermined filter with the predetermined coefficients of a predetermined spatial direction which is closest to the estimated spatial direction. 
 
     
     
       7. The method according to  claim 1 , which further comprises deriving a reference signal for an interfering sound from the second and/or third audio signals by differentiation. 
     
     
       8. The method according to  claim 1 , which further comprises deriving a reference signal for the useful signal from the second and/or third audio signals by totaling. 
     
     
       9. The method according to  claim 8 , which further comprises using the reference signal for the useful signal for detecting voice activity. 
     
     
       10. The method according to  claim 1 , wherein the predetermined filter is a finite impulse response (FIR) filter. 
     
     
       11. The method according to  claim 1 , wherein the adaptive filter uses a least-mean-square (LMS) method for minimizing interfering sounds. 
     
     
       12. A hearing aid system, comprising:
 two hearing aid devices each having a transducer for receiving an acoustic signal and converting the acoustic signal in each instance to a first audio signal, one of said hearing aid devices provided for each ear of a user; 
 each of said hearing aid devices having a signal processing apparatus for processing audio signals and having a predetermined filter and an adaptive filter; 
 a signal connection for bi-directionally exchanging the first audio signals between said signal processing apparatuses of said hearing aid devices; and 
 the hearing aid system configured to execute the following steps:
 filter first audio signals with said predetermined filter predetermined for a defined spatial direction, so that second audio signals are generated, said predetermined filter configured in such a manner that components of a useful signal in the second audio signals are equalized to a greater degree than in the first audio signals; and 
 filtering the second audio signals with said adaptive filter, so that third audio signals are generated, said adaptive filter configured in such a manner that components of the useful signal in the third audio signals are equalized to a greater degree than in the second audio signals.